Unable to set a property to null with lazy loading enabled

[arabasso]

I'm running the following code:

...
var customer = context.Find<Customer>(viewModel.CustomerId);

if (viewModel.StatusId == 0)
{
    customer.Status = null;
}

else
{
    customer.Status = context.Find<CustomerStatus>(viewModel.StatusId);
}

context.Update(customer);
context.SaveChanges();
...

Does not work. It only works if I explicitly load the property:

var customer = context.Find<Customer>(viewModel.CustomerId);

context.Entry(customer).Reference(m => m.Status).Load();

if (viewModel.StatusId == 0)
{
    customer.Status = null;
}

else
{
    customer.Status = context.Find<CustomerStatus>(viewModel.StatusId);
}

context.Update(customer);
context.SaveChanges();

Steps to reproduce

• Enable lazy loading with UseLazyLoadingProxies

Further technical details

EF Core version: 3.1.5
Database provider: Pomelo.EntityFrameworkCore.MySql or MySql.Data.EntityFrameworkCore
Target framework: .NET Core 3.1
Operating system: Windows 10 Pro 2004
IDE: Visual Studio 2019 16.6.2

[ajcvickers]

Duplicate of #14086